Inorganic fiber insulation product

ABSTRACT

Insulation formed by blowing nodules of inorganic fiber insulation coated with a water or other liquid activated binder in intimate contact and having a low moisture content in the just installed insulation of less than about 20 wt. percent is disclosed. The majority of the nodules have a maximum dimension of about 0.5 inch and have particles or a fiber web of a water or other liquid activated adhesive on their outer surface producing a high tack value with a very low moisture content. The insulation can be used to insulate building structures, including vertical wall cavities of buildings, without having to use any insulation securing means. The high tack value permits the sprayed-on insulation to stick to even the most stick-resistant sheathing product. The low moisture content of less than 20 wt. percent and a density of less than about 3 lbs. per cubic foot permits rapid drying of the installed installation and a lower elapsed time before the wallboard can be installed, and the insulation has a low density to produce conventional R values of at least R 13. Methods of making dry nodules coated with the reactivatable adhesive are disclosed as are methods of using the dry nodules to insulate building cavities.

The present invention involves fibrous thermal and acoustic insulation produced by spray application, the resultant sprayed-in insulation and the method of making the latter.

BACKGROUND

It is conventional to pump or blow loose-fill fibrous insulation into attics, walls, wall cavities, etc. of houses and other buildings. It is also known to add powdered binder (adhesive), de-dusting oil, anti-static agents to clumps of fiberglass or other fibrous insulation prior to a blowing nozzle to prevent settling, static discharge and or to reduce dust in the area of application during installation. The application of a liquid binder dispersion, or water to activate pre-added powdered adhesives, to create adhesive/cohesive tack strength is also known. Such technology can be found in U.S. Pat. Nos. 4,710,4804, 4,804,695, 5,641,368 and others, but as stated in U.S. Pat. No. 5,952,418, at least one of these systems suffer from problems of blockage of adhesive nozzles and/or a blowing hose. When these systems are used to insulate cavities between vertical or generally vertical studs or other structural members, a high moisture content, as high as 50% of the dry weight of the just installed insulation, is required to cause the insulation to adhere properly to various substrates that comprise the wall cavities of the cavities or building structure. Such high moisture contents require long drying times, typically 2 or more days, before wall board can be installed to avoid potential mold related problems, such as mold growth on the paper facing of the wallboard.

It is also known to spray clumps of fiber glass insulation coated with water and a non-foaming binder into wall cavities followed by rolling at least about an inch of excess insulation thickness down to the thickness of the wall studs followed by spraying additional clumps of insulation into any thin spots or unfilled cavities and then rolling or scrubbing off excess thickness down to the thickness of the studs. As disclosed in U.S. Pat. No. 5,641,368, the installed insulation is reported to have a moisture content of less than about 35 wt. percent. When using lower moisture contents, the clumps do not adhere sufficiently to certain conventional linings of wall cavities causing collapse and lower productivity. Rolling spray applied insulation can result in spring-back in some areas and adds an undesirable additional step to the installation process, the additional step of spraying a second time slows the building installation process and adds substantial cost to the insulating part of the building process.

Cellulose products require installed densities ranging from 2 to 3 PCF to achieve an R-13 level in thermal insulation in a standard wall cavity. These products cannot achieve an R-15 level due to density limitations and thermal limitations of the cellulose material. Most existing loose-fill mineral fiber products require installed densities of at least about 1.2 to 1.5 PCF to achieve an R-13 level of insulation and densities ranging from about 1.8 to 2.5 PCF to achieve an R-15 level in a standard 2×4 cavity. Although high density is required for cellulose application, the cellulose material is usually lower in cost than most mineral fiber products in similar applications and at similar R-values levels. Therefore, a need exists for a low density, cost competitive inorganic fiber product to use instead of cellulose. The present invention provides this capability.

It is also known to blow dry or semi-dry loose fill insulation into wall cavities that are vertical or substantially vertical, by first installing a retaining means such as netting, cardboard baffles, or other physical means. Installing the restraining means requires an extra work day in a typical size house and substantially adds to the installed cost of the insulation. It is known to blow fiber glass nodules coated with water and binder, the binder added with the water, into cavities producing a just-installed insulation having a relatively low moisture content, compared to about 35 wt. percent.

With concerns of mold problems in walls of various kinds of structures reaching serious levels, a sprayed-on insulation, particularly an inorganic fiber insulation with low moisture sorption potential that contains a substantially lower moisture content soon after installation is much needed. A need also exists to ensure that the insulation material will uniformly fill the cavities within a given structure and adhere well to the walls of the cavity to avoid collapse, gaps, settling and voids, the presence of which will substantially degrade insulation performance. The material should also be cost competitive with high productivity to ensure commercial success. The present invention addresses these needs.

SUMMARY OF INVENTION

The present invention includes coated fibrous nodules coated with a reactivatable or remoistenable adhesive using processes of the invention and used in a process of the invention to make a sprayed-on thermal and acoustic insulation product having a very low just installed moisture content. The just installed insulation product is formed in place by spraying nodules comprised of inorganic fiber and a water reactivatable adhesive or binder, drying the coated nodules delivering the dry coated nodules to a nozzle or end of a transporting hose, spraying water or other reactivating liquid into the coated nodules to activate the reactivatable adhesive before the resultant insulating mixture impacts in the cavity or other surface being insulated. Intermediate steps of packaging the dry coated nodules and then after the packages of dry coated nodules are on the building site, opening the packages and dumping the dry coated nodules into a blowing machine are added to one or more of the processes of the invention. The coated nodules are made from inorganic fiber and most typically glass fibers. The inorganic fibers used to make the nodules can be virgin fiber, virgin fiber having a dedusting oil on their surfaces, and fibers bound together with a cured resin binder. These fibers can also have one or more other functional additives like one or more silicones, biocides, pesticides, fungicides, fire retardants, phase change materials, etc. in the binder, oil or on or with the virgin fibers. The terms reactivatable and remoistenable often mean essentially the same thing herein, but sometimes the adhesives used in the invention are described by some as reactivatable and by others as remoistenable. Both terms mean that the adhesive is activated or reactivated by contact with water or other activating liquids producing a tacky condition.

Novel features of the present invention include the size of the fibrous nodules and the small amount of water or activating liquid used to reactivate or remoisten the reactivatable adhesive, significantly less than heretofore used. The major portion of the weight of the nodules have a maximum dimension of one-half inch, to produce a very high tackiness, going into cavities within a building structure, more typically at least about 60 wt. percent of the nodules have a maximum dimension of 0.5 inch, even more typically at least about 70 wt. percent having nodules of this size, still more typically at least about 80 wt. percent having nodules of this size and most typically at least about 85 or 90 wt. percent having nodules having a diameter of less than about 0.5 inch The amount of moisture in the just installed insulation of the invention is typically less than about 20 wt. percent, usually less than about 17 wt. percent, more typically less than about 15 wt. percent, even more typically less than about 12 wt. percent, still more typically less than about 10 wt. percent and most typically less than about 7 wt. percent. The amount of reactivatable, remoistenable adhesive on the nodules and in the just installed insulation is less than 10 wt. percent, typically less than about 7 wt. percent and most typically in the range of about 5 to about 2 wt. percent. The density of the just installed insulation is less than about 3 PCF (after drying) and more typically less than about 2 PCF to produce insulation in the cavity of having an R value of at least 13 (about 1 PCF).

The dry coated nodules of fibrous insulation are produced by a hammer mill or other nodule making machine, first coated with a liquid activatable adhesive, dried and optionally packaged. Later the dry coated nodules are fed to a blowing wool machine and at the end of the transporting hose or nozzle on the end of said hose, the dry coated nodules are sprayed with an reactivating liquid, most typically water, or another activating liquid producing activated insulating nodules having very tacky surfaces causing the activated insulating nodules to adhere to the cavity surfaces and to each other on impact inside a cavity, producing intimate contact and producing just installed insulation having enough initial tack to resist slumping and collapse during installation and until enough moisture evaporates to form an even stronger bond. The activated insulating nodules also adhere to all types of cavity construction materials which is key to resisting rebound and collapse. The term “just installed” means within one hour, more typically within about 30 to 45 minutes and most typically about 10 to about 40 minutes of installation, and the term “generally vertical” includes angles of from about 60 degrees to 90 degrees, or vertical. The activated nodules of the invention can also be used to insulate ceiling, overhead, cavities. Up to one hour of time can be required to remove and test samples of the insulation, although often a sample can be taken and measured in less than about 15-30 minutes. Normally very little drying takes place in the just installed insulation during this initial hour of time.

The final insulation product of the invention has unique characteristics including:

1. Inorganic fiber of small diameters having very low moisture sorption potential to facilitate drying time and to minimize mold growth potential and producing high thermal performance at low densities to permit a variety of R-values in a standard wall cavity and at different widths and depths while meeting newly proposed building code requirements, and also producing shorter drying times than prior art wet sprayed in insulation.

2. Comprised of small nodules that permit a variety of commercial blowing machines, including those specifically designed for blowing cellulose insulation, to produce a uniform cavity fill, high quality surface appearance, a faster rate of application, minimal plugging potential and high thermal and acoustical performance. With the majority, or more, of the nodules having a maximum dimension of about one-half inch, more typically at least about 70 percent of the nodules are smaller than one-half inch, more typically at least about 80 percent and even more preferably at least about 90 percent. Most typically the majority of the nodules are smaller than one-quarter inch and the smaller the nodules the better with at least about 70 percent being smaller than one-quarter inch, at least about 80 percent and at least about 90 percent being this size is even better.

3. Small nodules bonded together with a liquid activated binder or adhesive while avoiding spray jet or nozzle plugging, providing excellent tackiness for adhering to each other and to all types of building substrate materials describes additional positive features of the invention.

Typically the binder is a water-based or hot melt reactivatable, remoistenable, adhesive, but any dry binder or dry adhesive capable of being reactivated with water or other liquid to reach a tackiness of the extent that the just installed insulation does not collapse or slump, are suitable. The binder/adhesive, usually including one or more resins or polymers should produce sufficient initial tackiness to permit vertical wall cavities, including even ceiling cavities, of various depths to be filled by spraying without settling, slumping or collapsing until the insulation is dry enough to apply the interior wall board, expanded metal or other board product. Typically the binder is present in an amount in the range of about 0.5 wt. percent to about 10 wt. percent (dry solids basis of the installed insulation product) and preferably the amount of water present in the just installed product is in the range of about 7-12 wt. percent. Importantly the just installed product of the present invention will have R values as high as about 15 while containing typically less than about 0.47-0.5 or 0.55 lbs. of liquid per standard wall cavity, more typically only about 0.12 to about 0.35 lbs. of water in a standard wall cavity. A standard wall cavity is formed by vertical commercially available standard 2×4s, 8 feet high and 16 inches on center. Hereafter the term “standard cavity” will be used to describe this size cavity The moisture content of the just installed insulation can be below about 2-5 wt. percent for some building substrate materials and for attic installations, but is often higher for vertical wall cavities. Also, more insulation material will be required to fill wall applications because of closer packing (see FIG. 6) of the coated nodules during installation versus attic installations. It is not necessarily just the percent moisture in the product that is critical to drying time of the just installed insulation, but rather the amount (lbs.) of water per standard cavity, or other unit volume, that is most critical.

Preferably the inorganic fibers having an average diameter of less than about 3 microns, more preferably an average diameter of about 2.5-2 microns or less and most preferably, for insulating performance, an average diameter of about 1 micron or less. Preferably the inorganic fibers are glass fibers, but other fibers including slag wool, mineral wool, rock wool, ceramic fibers and carbon fibers are included. Any kind of stable glass fibers are suitable but preferably the glass fibers contain at least about 8% B₂O₃ as an infrared blocker to enhance thermal performance at low installed densities. Other infrared radiation blocking constituents (reflecting, scattering and/or absorbing) can also be included in the glass chemistry or can be applied to the glass fiber as surface coatings, mixed with the glass fibers or introduced in the water containing the resin adhesive to enhance thermal performance. Other performance enhancing additives can also be applied to the glass surface or nodule surface or mixed with the glass fibers. These can include for example microencapsulated phase change materials, fire retardants, fungicides or pesticides.

Typically the dry nodules are smaller than about one inch diameter, more typically most or all of the coated nodules less than about one-half inch in length, width and thickness, or diameter, but larger sizes can be used if an acceptable surface appearance can be obtained. Most desirably a majority, or more, of the nodules are less than one-quarter inch in length, width and thickness, or diameter. While the size of the nodules is important to optimum performance in most all aspects, it is difficult to determine the actual dimensions of a large number of nodules because of their irregular shape, their compressibility, and tendency to adhere together. Observance has indicated that most preferable size is that at least 90 percent of the nodules have a dimension of about one-quarter inch or less, but that percentage can also be at least 80, and at least 70. The smaller the nodules, the better the performance generally. The nodules of inorganic fibrous insulation can also contain conventional amounts of one or more anti-static agents, one or more of de-dusting oils, hydrophobic agents such as a silicone, biocides and fire retardants applied to the fibers, a binder holding the fibers together when that type of fiber glass insulation is used to form the nodules, or to the nodules in a conventional manner. By dry nodules is meant nodules having less than about 1 wt. percent moisture to bone dry, more typically less than about 0.5 percent moisture and most typically in the range of about 0.0 to about 0.3 wt. percent.

The coated nodules when sprayed into a cavity to form the present insulation product form into a uniform thermal/acoustical insulation mass in a wall cavity having a density preferably of 3 lbs./cu. ft. (PCF) or less, more preferably of 2 PCF or less and most preferably 1 PCF or less. The density will depend to some extent upon the R value desired. For a standard cavity the preferred product of the present invention will produce a installed insulation in a standard cavity that when dry will have a density within the range of about 0.8 to about 1 PCF and an R value of about 13, or a density in the range of about 1.5 to about 1.8 PCF and an R value of about 15. This low density and a low moisture content results in a superior insulation product having low cost and a substantially faster drying time than previous wet blown-in wall cavity insulation.

When the word “about” is used herein it is meant that the amount or condition it modifies can vary some beyond that so long as the advantages of the invention are realized. Practically, there is rarely the time or resources available to very precisely determine the limits of all the parameters of ones invention because to do would require an effort far greater than can be justified at the time the invention is being developed to a commercial reality. The skilled artisan understands this and expects that the disclosed results of the invention might extend, at least somewhat, beyond one or more of the limits disclosed. Later, having the benefit of the inventors disclosure and understanding the inventive concept and embodiments disclosed including the best mode known to the inventor, the inventor and others can, without inventive effort, explore beyond the limits disclosed to determine if the invention is realized beyond those limits and, when embodiments are found to be without any unexpected characteristics, those embodiments are within the meaning of the term about as used herein. It is not difficult for the artisan or others to determine whether such an embodiment is either as expected or, because of either a break in the continuity of results or one or more features that are significantly better than reported by the inventor, is surprising and thus an unobvious teaching leading to a further advance in the art.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic view of an exemplary embodiment of a system for forming an insulation particle/air suspension.

FIG. 2 is a schematic of processes of the invention for making coated insulation nodules of the invention.

FIG. 3 is a schematic of one process of the invention for making coated insulation nodules of the invention.

FIG. 4 is a schematic of other processes for making dry coated insulation nodules of the invention.

FIG. 5 is an approximation of a just installed prior art insulation clumps in a portion of a building cavity.

FIG. 6 is an approximation of a just installed insulation comprising nodules and low moisture content according to the present invention.

DETAILED DESCRIPTION OF THE INVENTION

It is well known how to make loose-fill clumps of inorganic fibers for forming blown-in insulation. The inorganic fiber used in the present invention can be glass fibers, mineral wool, slag wool, or a ceramic fiber and preferably is fiberglass, most preferably containing in the glass a boron oxide content of at least about 8 percent. Preferably the fiber has a mean or average fiber diameter less than or equal to about 3 microns such as an average fiber diameter of 2.5 microns or less, more preferably equal to or about 2 microns, even more preferably equal to or less than about 1.5 microns with the most preferred mean diameter being about 1 micron to produces an insulation product having high thermal performance at low installed densities. FIG. 5 is an approximation of just installed insulation comprising fiber clumps 11 in a portion of a building cavity. The clumps 11 do not pack together well because of their larger size.

Nodules are defined above as very small bundles of insulation fibers that are equal to or less than about one inch, more typically most of the nodules are not greater than about ½ inch in length, width and thickness or diameter and most typically almost all of the nodules are this latter size or smaller, i.e. at least about 90 percent of the nodules. Preferably, the size of at least the majority of the nodules in all three dimensions or diameter is ¼ inch or less. Clumps are defined as having a physical size greater than that of these nodules of fiber. Most conventional mineral fiber loose-fill insulation products designed for attic application consist of clumps of fibrous material. These types of products will not provide the desired uniformity and quality surface appearance required for spray-applied application to meet stringent inspection standards and to ensure consistent thermal performance. In addition, if these products were used for spray applied application, they would produce just installed insulation looking like that shown in FIG. 5, not be readily able to closely pack in the building cavity, i.e. fit together snug and tight as do the nodules 8 shown in the just installed insulation 12 formed according to the invention and shown in FIG. 6. The larger clumps 11 would be more prone to one or more of plugging, not allowing for adequate wetting when binder is applied and/or not providing the required R-value at cost competitive installed densities.

Referring to FIG. 1 an exemplary system 1 for forming just installed insulation in accordance with the present invention in building cavities is shown. A blowing machine 2 can be connected to receive insulation nodules of the invention. The blowing machine 2 suspends the coated insulation nodules in air and blows the suspension from an outlet 3. An optional booster fan 4 can be connected to directly receive a flow of the suspension from the outlet 3 of the blowing machine 2. A hose 6 can be connected to receive the flow of the suspension from the booster fan 4, and convey such flow proximate to the surface 12 to be insulated, such as a surface of a wall cavity. The suspension 8 can be directed at the surface 12. The suspension 8 can be ejected from the hose 6 via an optional nozzle 5 connected to the end of the hose 6. A the optional nozzle 5 is not necessary because one or more liquid spray tips or jets can be fastened to a metal or polymer collar (conventional and not shown) on the hose at or near its exit end, also having a handle, if desired, but a nozzle is desirable to more accurately place the suspension of the coated, tacky insulating nodules. Water or another reactivating liquid is applied to the coated insulation nodules of the suspension 8 by at least one spray tip arranged at the nozzle 5. The water or other liquid reactivates or remoistens the reactivatable adhesive coating on the nodules to produce a tacky surface. The reactivating or remoistening liquid is supplied from a source 20 using a pressure line 7 and a pump 22. A relatively low amount of reactivating, remoistening liquid is added to the coated insulation nodules to produce a moisture or liquid content in the just installed insulation 14.

Each blowing machine has an outlet through which the nodules of insulation are ejected as a rapidly moving air suspension. One end of a hose is connected to the outlet. The other end of the hose can be in the location that the operator will need for installing the insulation. The blowing machine hose can be up to about 200 feet long and can have a diameter of about 2.5 inches to about 4 inches or so, depending upon the type of blowing machine and the intended use or particular application. The blowing machine mixes the nodules with air and blows the resulting air suspension out the outlet and through the hose. A nozzle is normally attached to the end of the hose, the nozzle usually having one or more handles for the operator to hold to aim the nozzle in the proper direction and orientation for spraying the cavities. Nozzles are known as is shown in U.S. Pat. Nos. 5,641,368 and 5,921,055. The nozzle used in the present invention has preferably two or more jet spray tips for spraying the water or other liquid onto the nodules of fibrous insulation near the exit end of the nozzle, preferably at or past the exit end. Other non-aqueous liquids suitable for activating the adhesive or binder includes liquids that activate the adhesive, but that are not explosive or an environmental hazard.

An adjustable rate pump connected to a use tank of water or activating liquid, or directly to a water supply to provide water or other liquid at the proper rate and pressure to the jet spray tips through one or more flexible hoses to properly coat the nodules with the desired amount of water or other liquid. One or more jet spray tips can be used to apply the water or liquid to the nodules at an elevated pressure supplied by the pump. Usually two or three spray tips are used opposite each other across the moving column of suspended clumps and/or nodules. Many different types of jet spray tips can be used and one that performs well is Spray Systems Company's 25 degree flat spray Unijet® tip. Another jet spray tip that is suitable is Spray Systems Company's 65 degree Unijet® tip.

The resultant wet binder or adhesive coated clumps and/or nodules of mineral fiber insulation contain a moisture content of less than about 20-25 wt. percent, based on the dry weight of the clumps and/or nodules, preferably less than about 12 percent, more preferably less than about 10 wt. percent and can be down to less than about 7 weight percent or even lower depending on the type of building cavity or surface being insulated and depending on the nature of the binder or adhesive. At these weight percentages, the initial water content in a standard cavity would range from about 0.12 to about 0.35 lbs. for an R13 application for installed density ranging from about 0.8 to about 1.0 PCF.

Fibrous loose-fill insulation is subject to all three modes of heat transfer—radiation, conduction and convection. Convection can be minimized by reducing size of the nodules of loose insulation and preferably by producing more consistently sized nodules to limit potential air passages (voids) that can occur within the installed material. Convection is also minimized with a uniform cavity fill with no gaps or voids caused by bridging of the clumps, and with a fill that is such that the insulation is even with the framing faces when installation is complete. Small nodule size also makes this possible. If convection is kept to a minimum, infrared thermal radiation and conduction are the remaining modes of heat transfer that need to be reduced to ensure best thermal performance, i.e., high thermal resistance (R-value). Some studies have shown that if convection is minimized, infrared radiation can account for about 30 to 40% of the heat flow through a fibrous insulation product. The remaining portion of the heat flow would then be due to still air and solid material conduction. From a physics standpoint, a fibrous insulation product with fine fiber has more surface area per mass of fiberized material to intercept and scatter infrared thermal radiation versus a product with coarser fiber diameter. This is especially effective if the chemistry of the fiber enhances the scattering and absorption of the radiation. For glass fibers, having 8% or higher concentrations of B₂O₃ in the glass chemistry greatly enhances the scattering and absorption of infrared thermal radiation. Surface coatings can also be applied to fibers to enhance scattering and absorption. A network of fine fiber is also more effective in creating pockets of still air and minimizing sold conduction through the individual fibers. The combination of improved radiation scattering, minimal air movement and minimized sold conduction produces very good thermal performance. An additional benefit of fine fiber is that the material can be installed at low densities to achieve standard R-value requirements, e.g., R-13 @ 0.8 to 1.0 PCF installed density or R-15 @ 1.5 to 1.8 PCF in a standard 2×4, 8′ high, 16″ on center cavity.

The nodules of fibrous insulation for use in the present invention are made with conventional hammer mills, slicer-dicers or equivalent material processing machines. A slicer-dicer cuts or shears blankets, a layer, of fiberglass insulation into small cube-like or other three dimensional pieces. Hammer mills and the like tear and shear virgin fiber glass or fiber glass blanket and tend to roll them into generally irregular spherical or rounded nodules, keeping most pieces in the mill until they achieve a pre-selected size. The nodule size is controlled using an exit screen containing the appropriate opening size to produce the desired nodule size. Any type of fiberglass insulation product can be processed in a hammer mill, i.e. blanket in which the glass fibers are bonded together with a cured resin, usually a thermoset resin, or a blanket of virgin fiberglass containing only de-dusting oil, silicone anti-stat, etc. Also, the binder used to bond the glass fibers together in the blanket can also contain one or more of functional ingredients such as IR barrier agents, anti-static agents, anti-fungal agents, biocides, de-dusting agents, pigments colorants, microencapsulated phase change material (such as Micronal™ PCM from BASF), etc., or one or more of these functional ingredients can be applied to the fibers either before or during processing in the hammer mill or other reducing device.

The size of openings in an exit screen in the hammer mill or similar device are varied to produce the desired nodule size. The preferred size depends on the cutting and shearing characteristics of the fibrous material. For fiberglass material, an exit screen size with square openings ranging from 1 to 3 inches can be used to produce nodule or clump sizes that range in size from ⅛ inch to ¾ inch. The preferred screen size used to make the nodules making up the insulation product of the invention preferably has a continual pattern of 2 inch×2 inch squares or 2 inch diameter holes. This 2 inch screen opening size produces nodules of ¼ inch or smaller size range.

The nodules of inorganic fiber such as fiberglass can also be made from what is called “virgin blowing wool”. Virgin blowing wool is made by making glass fiber insulation in a conventional manner except that one or more dry, but water or liquid activatable, water based adhesive or hot melt adhesive is applied to the fibers. In addition, a de-dusting oil and/or an anti-stat like silicone is applied to the fibers and the resultant fibrous blanket is then run through the hammer mill or similar processing device. The water based or hot melt reactivatable adhesive and other agents can also be applied to the fibers such as a fungicide, a biocide, filler particles and/or IR retarding additives, either soon before or immediately before blowing through a nozzle or end of a hose, or earlier in the hammer mill or other nodulating machine. Although the activatable adhesive or binder can be dispersed throughout the nodules, it is desirable to have the adhesive or binder concentrated at the surface of the nodules.

The inorganic fibers used in the present invention can be glass, mineral wool, slag wool, or a ceramic fiber and preferably is fiberglass. Inorganic fibrous material has low moisture sorption (absorption and adsorption) potential, typically less the 5% moisture gain by weight. The application of fiber surface waterproofing agents, such as silicone or de-dusting oils can further reduce moisture sorption potential. A material with low moisture sorption is preferred for spray-applied application to allow for fast drying and to limit moisture storage capacity, which greatly limits the potential for mold growth.

The particles or nodules of the present invention are smaller and greater in number than used before as a blown in insulation product. Nodules are defined as very small diameter generally spherical, but having one or more radii, fibrous insulation of ¼ inch and smaller as described in the Summary. Having a small nodule size is important to achieve good installed thermal performance. With a small nodule size, the material will effectively fill around obstructions in building cavities such as electrical boxes, wiring and plumbing, thus, providing a uniform void-free fill. A small nodule size also allows the installer to maintain surface flatness and uniformity in the insulation product after excess material is removed from the cavity framing faces. Additional benefits from having small nodule size are reduced plugging potential as the material flows through the components of the blowing equipment, reduced potential for gaps and bridging voids along the framing members and elsewhere, more consistent R-values, improved air flow resistance and better wetting characteristics when adhesive is applied. The nodules of the present invention are smaller and greater in number than heretofore coated with water containing a water soluble adhesive and used to make a blown in insulation product.

In the invention the just installed insulation is obtained with nodules of insulation that are coated with a reactivatable, remoistenable adhesive. Production of the small coated nodules that make up the insulation product can be produced as shown in FIGS. 2 and 3. Inorganic fibers of the type described above can be made by any one of a plethora of fiber making systems 10 and any of the fibers meeting the above description are usable in the invention. The systems 10 produce virgin inorganic fibers 16 that can either be sent directly to a nodulating machine like a hammer mill, first coated with dedusting oil and/or other additives in an intermediate step 24 or first sprayed with a binder step 26, submitted to a drying and curing step 28, and a trimming or scrapping step 30 and then sent to the nodulating machine, such as hammer mill 18. The nodulating machine, such as a hammer mill 18 having an exit screen having appropriate hole sizes therein produces nodules of the desired size described above. The exiting nodules 32 are then coated with a reactivatable adhesive in a coating step 34, optionally dried or cooled in step 36 to set the adhesive coating on the surface of the nodules 32 to produce coated nodules 38. The reactivatable adhesive is predominately on the outer surface of the nodules.

Applying a reactivatable adhesive to the nodules 32 can be done by any of a number of alternative ways. If the reactivatable adhesive desired is available as a dry powder, the powder can be applied to the surfaces of the insulation nodules 32 by either blowing or mechanically slinging the powder onto the nodules 32 while they are falling through the air or are being tumbled or suspended in a mixer or insulation blowing machine. The dry powder particles attach to the surface portion of the nodules 32 by lodging in the openings between the fibers and by attaching to the fibers with static forces. Spraying the reactivatable adhesive in the form of a aqueous or solvent solution or suspension or a molten hot melt onto the nodules 32 as they fall past spray heads works better. When the reactivatable adhesive is water based it must be thoroughly dried before the coated insulation nodules are packaged to prevent their sticking together too tightly in the packages. This can be accomplished with a counter flow of hot air at a temperature sufficient to rapidly dry the coated nodules without deteriorating the adhesive. When the adhesive is applied as a molten hot melt, the coated nodules need to be cooled cooled sufficiently to solidify the adhesive before the nodules are collected together. The nodules 38 coated with a reactivatable adhesive can then go to a hopper above an insulating blowing machine or directly to the insulating blowing machine 2, or to packaging equipment 40.

There are many alternative ways to produce the reactivatable adhesive coated nodules. One alternative way is to feed, or dump bags or bales of compressed, loose-fill nodules of inorganic fiber loose-fill insulation made as described above into a hopper or mixer similar to conventional blowing machines. Reactivatable or remoistenable adhesives are sprayed or otherwise introduced into the hopper or mixer and the mixture is tumbled and then dried to produce fibrous nodules coated with the reactivatable adhesive. Spray applied reactivatable or remoistenable hot melt adhesives are desirable because there is no water to dry out—cool air sprayed onto the nodules will solidify the hot melt remoistenable adhesive very quickly leaving most of the adhesive on the outer surface of the nodules where it is most needed and where, upon remoistening, it produces the most tackiness for the nodules to stick together in the building cavity. Hot melt adhesive spray equipment is well known and readily available from a number of sources.

Reactivatable or remoistenable adhesives are typically applied to stamps, tapes, labels, envelopes, etc., during their manufacture to facilitate subsequent application and/or closure of those products. H.B. Fuller offers both water-based and hot melt remoistenable adhesives for a variety of application and performance requirements. Typical of some of the remoistenable hot melt adhesives are disclosed in U.S. Pat. No. 5,459,184, the disclosure of which is herein incorporated by reference. Specific product examples from other suppliers like DynaTech Adhesives include water based products like FlexTac™ 272 and 7465.

Hot melt remoistenable adhesives can be applied to the surfaces of the nodules in the form of particles, molten droplets or a molten fine fibrous web, the latter by using conventional hot melt spray nozzles and other spray, feeder, spreader or slining equipment. For example, hot melt remoistenable adhesives can be melted using a Nordson Series 3500 melt tank, the melted adhesive can then be pumped to a bank of Nordson Universal CF spray nozzles or other nozzles such as ITW Dynatec Laminated Plate Technology

Following drying and/or cooling, the nodules coated with a reactivatable, remoistenable adhesive are packaged in bags, barrels or boxes. The coated nodules need to be packaged such that the package prevents moisture or high humidity from penetrating the packaging material and activating the adhesive coating on the surface of the coated nodules that would cause the nodules to bond together forming one or more lumps of bonded together compressed nodules. Packaging materials, normally plastic, are well known for this purpose. The barrier material can be only a plastic bag or plastic drum, or a plastic bag inside another container such as Kraft boxes, bags or drums.

The resultant coated nodules of inorganic fiber insulation contain, also in an outer region of the nodules an amount of resin or adhesive content of less than about 10 wt. percent, based on the dry weight of the nodules, more typically less than about 4-5 wt. percent and most typically less than about 2 wt. percent for installed densities ranging from about 0.8 to about 2-3 PCF.

Some methods of making coated insulation nodules of the invention are illustrated in FIG. 3. Fibrous insulation nodules 32 are made in a nodulating machine such as a hammer mill 18. The insulation nodules 32 can be collected in any suitable manner such as with a belt conveyor 42, or can be dropped directly through a coating zone 44. In the coating zone 44, the insulation nodules 32 are coated with a reactivatable adhesive using either one or more banks of heated nozzles 46 spraying molten hot melt reactivatable adhesive from a heated hot melt tank 45 and a pump 47 via a heated line 48, or with a reactivatable adhesive in solution or suspension in a liquid such as water or solvent using one or more banks of spray jets 50 being fed with the solution or suspension from a holding tank 52, pump 53, and line 54.

The coated insulation nodules 55 continue to free fall through a chamber 56 where they encounter a counter flow of hot, drying air, or when the reactivatable adhesive is a molten hot melt, cooling air, supplied by a manifold 59 surrounding the chamber 56 and communicating with the interior of the chamber 56 via a continuous or interrupted circumferential slot or a plurality of spaced apart hollow conduits. A stream of hot or cool air 60 is supplied to the manifold 59 in known manner. The resultant hot, or cool, reactivatable adhesive coated insulation nodules 62 of the invention continue to fall into a collection chamber 64. When the coated nodules 62 are hot, they can optionally be cooled by a flow of cool air 66 via a manifold 65 surrounding a lower portion the collection chamber 64. One or more agitator/feeders 67 in the bottom of the collection chamber 64 feed the coated nodules 62 at a desired rate into either conventional packaging equipment (not shown) to produce sealed packages 68 of compressed, coated nodules 62 of the invention, or into an insulation blowing machine.

As shown in FIG. 4, nodules of inorganic fibrous insulation, made by nodulating either virgin fiber or fiber bonded with a dried and cured resin in the form of trim or scrap, or a mixture thereof, is fed into a nodulating machine such as a hammer mill 18 containing an exit screen to produce nodules 32 having a diameter of less than about ½ inch are fed either directly or indirectly into an insulation blowing machine 2. These nodules can be first fed into packaging equipment 40 to produce packages 41 of compressed nodules 32. The nodules are suspended in air and blown through a hose 6 and as they exit the hose 6, or an optional nozzle 5, are spray coated with sprays 51, coming from spray jets 50, of reactivatable adhesive in the form of either a molten hot melt or a solution or a liquid suspension of reactivatable adhesive particles. The coated nodules 55 are then allowed to drop through a chamber 56 against a counter flow 58 of either hot air to dry the coating or a cool air to solidify the coating. The dried and/or cooled coated nodules 62 are then collected in a hopper 64 and, with an agitating feeder 67, are fed into packaging equipment 40 that compresses the coated nodules 62 in moisture proof bags, boxes or drums for storage or shipment to a building job site.

EXAMPLE 1

Virgin glass fiber having an average fiber diameter of 2 microns and made by a conventional process such as described in U.S. Pat. No. 4,058,386, is fed to a hammer mill containing an exit screen having hole diameters sized to produce nodules of one half inch and smaller diameters. These nodules are allowed to fall in front of a bank of hot melt adhesive spray heads spraying H.B. Fuller Co.'s NP 2255 remoistenable hot melt adhesive to coat the nodules. The remoistenable hot melt is applied to the falling nodules in a process like that illustrated in FIG. 3 using a bank of 20 ITW spray heads, each equipped with #109448 nozzles and 20 psi compressed air, delivering, for example, about 150 grams per minute of fiberized H.B. Fuller's NP 2255 hot melt across a 22-24 inch wide flow of falling nodules. Counter flow of cool air in a chamber beneath the spray zone rapidly solidifies the hot melt web on the surface of the fibrous insulation nodules to produce reactivatable coated fiberous insulation nodules.

EXAMPLE 2

A moisture activated envelope flap type adhesive such as Dyna-Tech™ Flextac™ 272 or 7465 is spray applied to fiberglass nodules like those described in Example 1. These adhesives are water based and are pumped to spray jets with a pump as shown in FIG. 3. The adhesives have solids contents of 55% or more, therefore the coated nodules dry very fast when sprayed onto hot nodules, or when the coated nodules are subjected to a counter flow of hot air, to produce reactivatable adhesive coated insulation nodules.

EXAMPLE 3

As shown in FIG. 4, nodules of inorganic fibrous insulation, either virgin fiber or fiber bonded with a dried and cured resin in the form of trim or scrap, are fed into a nodulating machine such as a hammer mill containing an exit screen to produce fibrous insulation nodules having a diameter of less than about ½ inch. These nodules are then either fed into packaging equipment or directly into an insulation blowing machine. The nodules are suspended in air and blown through a hose. As they exit the hose, or an optional nozzle, the nozzles are spray coated with sprays of reactivatable adhesive in the form of either a molten hot melt or a solution or a liquid suspension of reactivatable adhesive particles as described in Examples 1 and 2. The coated nodules are then allowed to drop through a chamber against a counter flow of either hot air to dry the coating or a cool air to solidify the coating. The coated nodules are then collected and fed into packaging equipment that compresses the coated nodules in moisture proof bags, boxes, or drums, for storage or shipment to a building job site.

EXAMPLE 4

A Unisul Volumatic® III insulation blowing machine equipped with 150 feet of 4 inch diameter hose is used to produce an insulation mass flow rate of approximately 18 lbs/minute of the reactivatable adhesive coated insulation nodules of Examples 1, 2, and 3, each comprising glass fibers having an average fiber diameter of 2 microns and an average nodule diameter in the range of about 0.25 to about 0.6 inch. The glass fiber in the nodules contains an average boron oxide content of about 8.7 wt. percent.

The blowing machine is operated with the transmission in 3rd gear, with 100% of the available blower air delivered to the rotary airlock assembly and with the slide gate (feed gate) set at 12 inches. The blower and secondary gearbox speeds (RPM settings) on the blowing machine are set to the manufacturer's recommended settings of 1425 and 1050 rpm, respectively. The mass flow of insulation is allowed to freely flow through the blowing hose into a nozzle at the end of the blowing hose. Spray jets on the outside of the nozzle are used to spray water to the mass flow of coated nodule insulation as the coated nodules exit from the nozzle. The water is applied at a rate of about 0.25 gallons/minute with the use of a Spray Tech pump (model 0295003). The spray nozzle assembly consists of a 4 inch diameter tube, the end of which is surrounded by an annular manifold containing two Spray System Co. model TPU-65-015 spray tips screwed into threaded ports located 180 degrees apart on the manifold. The ports are set at a 30 degree angle to the centerline of the mass insulation flow direction. This allows the water to be sprayed and entrained into the mass flow of coated nodules without disrupting the flow characteristics of the nodules to provide an insulation to water ratio in the just installed product of about 9:1.

By moving the nozzle from bottom to top and with a side to side motion from the bottom of the cavity to the top, the wetted, activated coated nodules of insulation is directed into various 8 foot high cavities defined between 8 foot high vertical 2×4's or 2×6's spaced on 16 inch centers or 24 inch centers to achieve a consistent fill with about 2-3 inches of excess insulation material extending beyond faces of each vertical framing member. Standard SPF wood framing (2×4 or 2×6) is used to form the cavities of the test walls. Oriented Strand Board (OSB) sheathing is used as the back wall of each cavity. The spray nozzle is held approximately 6 feet away from the open cavity during the installation process. Shortly after installation, the excess material is removed with the use of a commercial rotary wall scrubber (Krendl™ model 349B). The removed excess material is vacuumed up using a 50 foot length of 4 inch diameter hose connected to a centrifugal vacuum fan (Wm. W. Meyer & Sons, Inc. Versa-Vac (11) for recycling. At this flow rate, installation times of about 10 to about 15 seconds are required to fill a standard cavity. This is a much shorter application time than heretofore possible with prior art products.

Using the described equipment set up, the just installed moisture content of the insulation in each test wall is about 10-15 wt.% on an oven dry mass basis. Measurement is accomplished with the use of a load cell connected to a chain hoist. A large oven is used to dry the samples after the initial weights are taken. Over the 10-15% range, approximately 0.25 to 0.35 lbs of water exists in a standard 8 foot high, 16 inch on center 2×4 wall cavity. The oven dry density of the installed material is in the range from 0.9 to 1.1 PCF. Thermal testing on various samples in this same density range shows that the material provides an R-13 level of insulation in a standard 2×4 cavity. Loss On Ignition (LOI) testing indicates that approximately 2 to 3% adhesive solids exists in the installed material. With this content of adhesive solids, no problems are encountered with any installed material falling out of the wall cavities or with any post-installation settling or fallout in both 2×4 and 2×6 cavities. As the installed insulation dries, the adhesive provides still further bond strength and integrity in the insulation. The present invention, in applications at the lowest densities disclosed, will exhibit sufficient integrity to resist settling, shrinkage, or collapse in the cavity, even at a depth of 6 inches or more.

At a distance 6 foot from the cavity face densities in a range from 0.8 to 1.2 PCF can be consistently obtained. At 4 feet away, densities ranging from 1.3 to 1.5 PCF can be obtained and at 2 feet away, densities ranging from 1.6 to 1.9 PCF are achieveable. This ability to vary the installed density allows respective R-values of R-13, R-14 and R-15 to be obtained in standard 2×4 cavities. The results of this Example are found in Tables 1 and 2 below.

TABLE 1 Low Density Installation (nozzle position 6 feet from wall) 2 × 4, 2 × 4 2 × 6, 16″ O.C. 24″ O.C. 16″ O.C. 2 × 6, 24″ O.C. Installed 10–15 10–15 10–15 10–15 Moisture, % Installed Water 0.25–0.35  0.4–0.55  0.4–0.55 0.6–0.9 Weight, lbs/cav. Installation Time, 10 15 15 24 seconds/cavity Dry Insulation 0.8–0.9 0.8–0.9 0.8–0.9 0.8–0.9 Density, PCF R-value 13 13 20 20

The water spray onto the coated nodules and the dry coated nodules coming to the nozzle, i.e. ratio of mass flow of liquid to mass flow of dry nodules.

TABLE 2 High Density Installation (nozzle position about 2 feet from cavity back wall) 2 × 4, 2 × 6, 2 × 6, 16″ O.C. 2 × 4 24″ O.C. 16″ O.C. 24″ O.C. Installed 10–15 10–15 10–15 10–15 Moisture, % Installed Water  0.5–0.75 0.75–1.1  0.75–1.1  1.2–1.8 Weight, lbs/cav. Installation Time, 21 32 33 51 seconds/cavity Dry Insulation 1.7–1.8 1.7–1.8 1.7–1.8 1.7–1.8 Density, pcf R-value 15 15 23 23

In addition to the equipment set up previously described, numerous other combinations of pump flow rates, adhesive to water ratios, spray nozzle configurations, blowing machine settings, blowing machine types, adhesives and installation techniques can be used to achieve similar installed densities and similar or lower moisture levels. The particular settings described above primarily resulted from conducting a series of designed experiments to identify optimal settings that would deliver desired installation and performance characteristics of insulation material similar to that disclosed herein. The above results are demonstrative of the very low installed density, the very low installed cavity moisture weight and the very fast installation that is achievable with the present invention in comparison to the prior art. Installed moisture levels as low as about 2% can be obtained, but at some expense of other desired characteristics such as installation time and/or adhesive cost.

When filling wall cavities with sprayed-on insulation it is necessary to spray an excess of insulation nodules to make sure each cavity is fully filled. This requires that the excess insulation be either removed, or compressed to be even with the face of the studs after spraying and before the adhesive coating on the clumps or nodules dries to enable wall board, or other facing board to lie flush on the faces of the studs. As confirmed in U.S. Pat. No. 5,641,368, it has been found that a powered scrubber conventionally used to remove excess thickness of sprayed insulation will not work with conventional sprayed-on loose-fill fiberglass insulation because the powered reverse rotating action of the scrubber often tears large chunks of the fiberglass from the cavity. A scrubber is a rotating brush-like device that is long enough to span two adjacent studs. Although called a scrubber, water or other liquid is not involved in its use.

The use of a scrubber with the product of the present invention would not result in the reported problem. Because of the higher tackiness and small size of the nodules that form the insulation product of this invention, and the absence of voids caused by bridging, a scrubber is perfectly acceptable for removing excess insulation. Scrubbers do not tend to tear out large chunks from the insulation between the studs. It is not necessary to roll the just installed insulation of the present invention to reduce the thickness to the desired amount and preferably it is not rolled or compressed by any other means. These same features minimize slumping and collapse of the insulation during formation. Preferably, any excess thickness is removed using a scrubber or other functionally equivalent means.

As confirmed in the just above mentioned patent and others, it has been found in the past that excess adhesive was required to coat clumps of fiberglass containing a silicone, but an additional aspect of the present invention is that the clumps and/or nodules of insulation can contain silicone which is desirable for the waterproofing function that the silicone conventionally produces.

Biocide and/or desiccant agents can be added to the material during manufacturing or during installation to provide additional protection against potential mold growth and to potentially protect adjacent substrate materials (framing, sheathing, etc.) from potential mold growth.

With some or all of these unique attributes, a uniform cavity fill can be obtained over a wide range of installed R-values at low installed densities, having low moisture contents for fast drying. Mold growth potential is minimized by keeping the installed density low and the material cost is kept to a minimum.

Several examples and ranges of parameters of preferred embodiments of the present invention are described above, but it will be apparent to those of ordinary skill in the insulation field that many other embodiments may be possible by manipulation of the parameters of the invention. For example, although only a few different reactivatable adhesives are specifically disclosed, there are other suitable adhesives that will function in the same or very similar manner as in the above disclosed invention to produce the useful result of having high tack value. While most of the above discussion involves using the present invention in generally vertical wall cavities, this insulation product can also be used to insulate attics, ceilings, undersides or sloping roofs or any area that can be reached with a spray of the activated, air suspended nodule product. 

1. Just installed thermal and acoustical insulation comprising from about 0.5 to about 10 wt. percent of a water or other liquid activated adhesive on nodules comprising inorganic fiber having an average fiber diameter of about 2.5 microns or less, the majority of the nodules having a maximum dimension of about 0.5 inch, the nodules being in intimate contact with each other to form the just installed insulation, the just installed insulation having a liquid content of no more than 20 wt. percent, and the insulation having an R value of at least 13 and a density of less than about 3 PCF after drying.
 2. The insulation of claim 1 wherein the inorganic fibers comprise virgin glass fibers, the liquid content of the just installed insulation is in the range of about 7 to about 17 wt. percent.
 3. The insulation of claim 1 wherein the nodules comprise glass fibers bonded together with a cured resin at one or more of the locations where two or more of the fibers cross one another, the liquid content of the just installed insulation is in the range of about 7 to about 15 wt. percent and the nodules have less than about 5 wt. percent, on a dry basis, of water activated adhesive on their surface portion.
 4. The insulation of claim 1 wherein at least about 70 percent of the nodules have a maximum dimension of one-half inch.
 5. The insulation of claim 1 wherein at least about 80 percent of the nodules have a maximum dimension of one-half inch.
 6. The insulation of claim 1 wherein at least about 90 percent of the nodules have a maximum dimension of one-half inch.
 7. The insulation of claim 2 wherein at least about 70 percent of the nodules have a maximum dimension of one-half inch.
 8. The insulation of claim 2 wherein at least about 80 percent of the nodules have a maximum dimension of one-half inch.
 9. The insulation of claim 2 wherein at least about 90 percent of the nodules have a maximum dimension of one-half inch.
 10. The insulation of claim 3 wherein at least about 70 percent of the nodules have a maximum dimension of one-half inch.
 11. The insulation of claim 3 wherein at least about 80 percent of the nodules have a maximum dimension of one-half inch.
 12. The insulation of claim 3 wherein at least about 90 percent of the nodules have a maximum dimension of one-half inch.
 13. The insulation of claim 1 wherein the activated adhesive is a hot melt adhesive.
 14. The insulation of claim 2 wherein the activated adhesive is a hot melt adhesive.
 15. The insulation of claim 3 wherein the activated adhesive is a hot melt adhesive.
 16. The insulation of claim 5 wherein the activated adhesive is a hot melt adhesive.
 17. The insulation of claim 7 wherein the activated adhesive is a hot melt adhesive.
 18. The insulation of claim 10 wherein the activated adhesive is a hot melt adhesive.
 19. Dry nodules of inorganic fibers having an average diameter of about 2.5 microns or less, the major portion, by weight, of the nodules being no more than about 0.5 inch in diameter, comprising up to about 10 wt. percent of a water or other liquid reactivatable adhesive on the surface portion.
 20. The dry nodules of claim 19 wherein the adhesive is a water activatable hot melt adhesive.
 21. The dry nodules of claim 19 wherein the adhesive is a water reactivatable adhesive.
 22. The dry nodules of claim 19 wherein the reactivatable adhesive is present in an amount of less than about 7 wt. percent of the nodules.
 23. The dry nodules of claim 19 wherein the reactivatable adhesive is present in an amount of less than about 5 wt. percent of the nodules.
 24. The dry nodules of claim 20 wherein the reactivatable adhesive is present in an amount of less than about 7 wt. percent of the nodules.
 25. The dry nodules of claim 21 wherein the reactivatable adhesive is present in an amount of less than about 7 wt. percent of the nodules.
 26. The dry nodules of claim 19 wherein the reactivatable adhesive is present in an amount of less than about 4 wt. percent of the nodules.
 27. The dry nodules of claim 20 wherein the reactivatable adhesive is a hot melt adhesive present in an amount of less than about 5 wt. percent of the nodules.
 28. The dry nodules of claim 20 wherein the reactivatable adhesive is present in an amount of less than about 4 wt. percent of the nodules.
 29. The dry nodules of claim 21 wherein the reactivatable adhesive is present in an amount of less than about 5 wt. percent of the nodules.
 30. The dry nodules of claim 21 wherein the reactivatable adhesive is present in an amount of less than about 4 wt. percent of the nodules.
 31. The dry nodules of claim 19 wherein at least 70 wt. percent of the nodules have a diameter of less than about 0.5 inch.
 32. The dry nodules of claim 20 wherein at least 70 wt. percent of the nodules have a diameter of less than about 0.5 inch.
 33. The dry nodules of claim 21 wherein at least 70 wt. percent of the nodules have a diameter of less than about 0.5 inch.
 34. The dry nodules of claim 27 wherein at least 70 wt. percent of the nodules have a diameter of less than about 0.5 inch.
 35. The dry nodules of claim 29 wherein at least 70 wt. percent of the nodules have a diameter of less than about 0.5 inch.
 36. A method of insulating cavities in a building comprising blowing pieces of fibrous insulation comprising a water reactivatable adhesive through a hose while suspended in an air flow spraying water onto the pieces of fibrous insulation at the end of the hose or in a nozzle at the end of the hose and directing the wetted pieces of fibrous insulation into a building cavity to form just installed insulation, the improvement comprising using as the pieces of fibrous insulation dry nodules comprising inorganic fibers having an average diameter of about 2.5 microns or less, the major portion, by weight, of the nodules being less than about 0.5 inch in diameter, and wherein the amount of water sprayed onto the dry nodules is such that the moisture content of the just installed insulation is less than about 20 wt. percent and wherein the reactivatable adhesive is coated on the surface portion of the nodules and is present in an amount of 0.5 to about 10 wt. percent of the dry nodules.
 37. The method of claim 36 wherein the amount of water sprayed onto the dry nodules is such that the moisture content of the just installed insulation is less than about 17 wt. percent and the amount of reactivatable adhesive on the nodules is about 2 to about 5 wt. percent.
 38. The method of claim 36 wherein the water activatable adhesive is a hot melt adhesive.
 39. The method of claim 37 wherein the water activatable adhesive is a hot melt adhesive.
 40. A method of making dry nodules comprising inorganic fibers having an average diameter of about 2.5 microns or less, the major portion, by weight, of the nodules being no more than about 0.5 inch in diameter, and a water or other liquid reactivatable adhesive on the surface portion of the nodules comprising the steps of; 1) feeding virgin fiber or fiber bonded together with a dried and cured resin into a nodulating machine, 2) spraying, spreading or slinging the water or other liquid reactivatable adhesive onto the surface portion of the nodules while the nodules are free falling or tumbling in a mixer to produce nodules having a coating 0.5 to about 10 wt. percent of the water or other liquid reactivatable adhesive, and 3) drying or cooling the coated nodules to solidify the coating of activatable adhesive to produce dry nodules,
 41. The method of claim 40 comprising a further step of compressing and packaging the dry nodules in moisture proof containers.
 42. The method of claim 40 wherein at least 70 wt. percent of the nodules have a diameter of no more than about 0.5 inch.
 43. The method of claim 41 wherein at least 70 wt. percent of the nodules have a diameter of no more than about 0.5 inch.
 44. The method of claim 40 wherein the coating comprises about 2 to about 5 wt. percent of the dry nodules.
 45. The method of claim 43 wherein the coating comprises about 2 to about 5 wt. percent of the dry nodules. 